CHAPTER 1

QuickstartTHIS IS A CHAPTER for the impatient Evil Genius. Your new Arduino

board has arrived, and you are eager to have it do something.

So, without further ado…

Powering UpWhen you buy an Arduino Uno or Leonardo board, it is usually

preinstalled with a sample Blink program that will make the little built­in

LED flash. Figure 1­1 shows a pair of Arduino boards.

Figure 1­1 Arduinos Uno and Leonardo.

The light­emitting diode (LED) marked L is wired up to one of the digital

input­output sockets on the board. It is connected to digital pin 13. This

really limits pin 13 to being used as an output, but the LED only uses a

small amount of current, so you can still connect other things to that

connector.

All you need to do to get your Arduino up and running is supply it with

some power. The easiest way to do this is to plug in it into the Universal

Serial Bus (USB) port on your computer. For an Arduino Uno, you will

need a type A­to­type B USB lead. This is the same type of lead that is

normally used to connect a computer to a printer. For a Leonardo, you

will need a micro­USB connector. You may get some messages from your

operating system about finding new devices or hardware. Ignore these for

now.

If everything is working okay, the LED should blink once every two

seconds. The reason that new Arduino boards have this Blink sketch

already installed is to verify that the board works. Clicking the Reset

button should cause the LED to flicker momentarily. If this is the case, but

the LED does not flash, then it may just be that the board has not been

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programmed with the Blink sketch; but do not despair, as once everything

is installed, we are going to modify and install that script anyway as our

first project.

Installing the SoftwareNow that we have our Arduino working, let’s get the software installed so

that we can alter the Blink program and send it down to the board. The

exact procedure depends on what operating system you use on your

computer. But the basic principle is the same for all.

Install the Arduino development environment, which is the program that

you run on your computer that enables you to write sketches and

download them to the Arduino board.

Install the USB driver that allows the computer to talk to the Arduino’s

USB port. It uses this for programming and sending messages.

The Arduino website (www.arduino.cc(http://www.arduino.cc)) contains the

latest version of the software. In this book we have used Arduino 1.0.2.

Installation on Windows

The instructions that follow are for installing on Windows 7. The

approach is much the same for Vista and XP. The only part that can be a

little difficult is installing the drivers.

Follow the download link on the Arduino home page

(www.arduino.cc(http://www.arduino.cc)), and select the download for

Windows. This will start the download of the Zip archive containing the

Arduino software, as shown in Figure 1­2. You may well be downloading a

more recent version of the software than the version 1.0.2 shown

(misleadingly, the Arduino team have not got around to renaming the Zip

file yet).

Figure 1­2 Downloading the Arduino software for Windows.

The Arduino software does not distinguish between different versions of

Windows. The download should work for all versions, from Windows XP

onward. The following instructions are for Windows 7.

Select the Save option from the dialog, and save the Zip file onto your

desktop. The folder contained in the Zip file will become your main

Arduino directory, so now unzip it onto your Desktop. You can move it

somewhere else later if you wish.

You can do this in Windows by right­clicking the Zip file to show the

menu in Figure 1­3 and selecting the Extract All option. This will open the

Extraction Wizard, shown in Figure 1­4.

Figure 1­3 The Extract All menu option in Windows.

Figure 1­4 Extracting the Arduino file in Windows.

Extract the files to your Desktop.

This will create a new directory for this version of Arduino (in this case,

1.0.2) on your Desktop. You can, if you wish, have multiple versions of

Arduino installed at the same time, each in its own folder. Updates of

Arduino are fairly infrequent and historically have always kept pretty

good compatibility with earlier versions of the software. So unless there is

a new feature of the software that you want to use, or you have been

having problems, it is by no means essential to keep up with the latest

version.

Now that we have got the Arduino folder in the right place, we need to

install the USB drivers. If you have not already done so, plug your

Leonardo or Uno into your computer. Depending on your version of

Windows, there may be some halfhearted attempt by the operating system

to install drivers. Just cancel this at the earliest opportunity; it is unlikely

to work. Instead, you need to open the Device Manager. This is accessed

in different ways depending on your version of Windows. In Windows 7,

you first have to open the Control Panel, then select the option to view

Icons, and you should find the Device Manager in the list.

Under the section “Other Devices,” you should see an icon for “Unknown

Device” with a little yellow warning triangle next to it. This is your

Arduino (Figure 1­5).

Figure 1­5 The Windows Device Manager.

Right­click on the “Unknown Device” and select the option “Update

Driver Software.” You will then be prompted to either “Search

automatically for updated driver software” or “Browse my computer for

driver software.” Select the option to browse and navigate to the “arduino­

1.0.2­windows\arduino1.0.2\drivers” (Figure 1­6). Change the version

numbers if you are using a different version of Arduino.

Figure 1­6 Browsing for the USB drivers.

Click “Next,” and you may get a security warning; if so, allow the software

to be installed. Once the software has been installed, you will get a

confirmation message like the one in Figure 1­7. Although the message

will be different for a Leonardo, the procedure is identical.

Figure 1­7 The USB driver Installed successfully.

The Device Manager should now list the right name for the Arduino

(Figure 1­8).

Figure 1­8 The Device Manager showing the Arduino.

This is a one­off process; from now on, whenever you plug in your

Arduino board, its USB drivers will automatically be loaded, and the

Arduino will be ready for action.

Installation on Mac OS X

The process for installing the Arduino software on the Mac is a lot easier

than on the PC.

As before, the first step is to download the file. In the case of the Mac, it is

a Zip file. Once downloaded, double­click on the Zip file, which will

extract a single file called “Arduino.app.” This is the whole Arduino

application; just drag it into your Applications folder.

You can now find and launch the Arduino software in your Applications

folder. As you are going to use it frequently, you may wish to right­click its

icon in the dock and set it to “Keep in Dock.”

Installation on LINUX

There are many different LINUX distributions, and the instructions for

each distribution are a little different. The Arduino community has done a

great job of putting together sets of instructions for each distribution. So

follow the link below and select one of the ten (at the time of writing)

distributions on offer.

Configuring Your Arduino EnvironmentWhatever type of computer you use, you should now have the Arduino

software installed on it. You now need to make a few settings. You need to

specify the serial port that is connected to the Arduino board, and we need

to specify the type of Arduino board that we are using. But first, you need

to connect your Arduino to your computer using the USB lead or you will

not be able to select the serial port.

Next, start the Arduino software. In Windows, this means opening the

“Arduino” folder and clicking on the “Arduino” icon (selected in Figure 1­

9). You may prefer to make a shortcut for the Desktop.

Figure 1­9 Starting Arduino in Windows.

The serial port is set from the Tools menu, as shown in Figure 1­10 for the

Mac and in Figure 1­11 for Windows 7—the list of ports for LINUX is

similar to the Mac.

Figure 1­10 Setting the serial port on the Mac.

Figure 1­11 Setting the serial port on Windows.

If you use many USB or Bluetooth devices with your Mac, you are likely to

have quite a few options in this list. Select the item in the list that begins

with “dev/tty.usbserial.”

On Windows, the serial port can just be set to COM3 or COM4, whichever

shows up.

From the Tools menu, we can now select the board that we are going to

use, as shown in Figure 1­12.

Figure 1­12 Setting the board.

Downloading the Project SoftwareThe sketches (as programs are called in the Arduino world) used in the

book are available as a single Zip file download. The whole download is

less than a megabyte, so it makes sense to download the software for all of

the projects, even if you only intend to use a few. To download them,

browse to www.arduinoevilgenius.com(http://www.arduinoevilgenius.com) and

follow the download links for the second edition of this book.

Whatever your platform, the Arduino software expects to find all your

sketches in your “Documents” folder, contained within a folder called

“Arduino,” which the Arduino software will create the first time it is run.

So place the contents of the Zip file into that folder.

Note that each sketch comes in its own folders, and the sketches are

numbered by project.

Project 1Flashing LEDHaving assumed that we have successfully installed the software, we can

now start on our first exciting project. Actually, it’s not that exciting, but

we need to start somewhere, and this will ensure that we have everything

set up correctly to use our Arduino board.

We are going to modify the example Blink sketch that comes with

Arduino. We will increase the frequency of the blinking and then install

the modified sketch on our Arduino board. Rather than blink slowly, our

board will flash its LED quickly. We will then take the project a stage

further by using a bigger external LED and resistor rather than the tiny

built­in LED.

COMPONENTS AND EQUIPMENT

Software

First, we need to load the Blink sketch into the Arduino software. The

Blink sketch is included as an example when you install the Arduino

environment. So we can load it using the File menu, as shown in Figure 1­

13.

Figure 1­13 Loading the example Blink sketch.

The sketch will open in a separate window (Figure 1­14); you can, if you

like, now close the empty window that opened when Arduino started.

Figure 1­14 The Blink sketch.

The majority of the text in this sketch is in the form of comments.

Comments are not actually part of the program but explain what is going

on in the program to anyone reading the sketch.

Comments can be single­line comments that start after a // and continue

to the end of the line, or they can be multiline comments that start with a

/* and end some lines later with a */.

If all the comments in a sketch were to be removed, it would still work in

exactly the same way, but we use comments because they are useful to

anyone reading the sketch trying to work out what it does.

Before we start, a little word about vocabulary is required. The Arduino

community uses the word “sketch” in place of “program,” so from now on

I will refer to our Arduino programs as sketches. Occasionally I may refer

to “code.” Code is programmer speak for a section of a program or even a

generic term for what is written when creating a program. So someone

might say, “I wrote a program to do that,” or they could say, “I wrote some

code to do that.”

To modify the rate at which the LED will blink, we need to change the

value of the delay so in the two places in the sketch where we have

change the value in the parentheses to 200 so that it appears as

This is changing the delay between turning the LED on and off from 1000

milliseconds (1 second) to 200 milliseconds (1/5th of a second). In

Chapter 3 we will explore this sketch further, but for now, we will just

change the delay and download the sketch to the Arduino board.

With the board connected to your computer, click the Upload button on

the Arduino. This is shown in Figure 1­15. If everything is okay, there will

be a short pause, and then the two red LEDs on the board will start

flashing away furiously as the sketch is uploaded onto the board. This

should take around 5 to 10 seconds.

Figure 1­15 Uploading the sketch to the Arduino board.

If this does not happen, check the serial port and board type settings as

described in the previous sections.

When the completed sketch has been installed, the board will

automatically reset, and if everything has worked, you will see the LED for

digital port 13 start to flash much more quickly than before.

Hardware

At the moment, this doesn’t really seem like real electronics because the

hardware is all contained on the Arduino board. In this section we will

add an external LED to the board.

LEDs cannot simply have voltage applied to them; they must have a

current­limiting resistor attached. Both parts are readily available from

any electronics suppliers. The component order codes for a number of

suppliers are detailed in the Appendix.

The Arduino board connectors are designed to attach “shield” plug­in

boards. However, for experimentation purposes, they also allow wires or

component leads to be inserted directly into the sockets.

Figure 1­16 shows the schematic diagram for attaching the external LED.

Figure 1­16 Schematic diagram for an LED connected to the

Arduino board.

This kind of schematic diagram uses special symbols to represent the

electronic components. The LED appears rather like an arrow, which

indicates that light­emitting diodes, in common with all diodes, only allow

the current to flow in one direction. The little arrows next to the LED

symbol indicate that it emits light.

The resistor is just depicted as a rectangle. Resistors are also often shown

as a zigzag line. The rest of the lines on the diagram represent electrical

connections between the components. These connections may be lengths

of wire or tracks on a circuit board. In this case, they will just be the wires

of the components.

We can connect the components directly to the Arduino sockets between

the digital pin 12 and the GND pin, but first we need to connect one lead

of the LED to one lead of the resistor.

It does not matter which lead of the resistor is connected to the LED;

however, the LED must be connected the correct way. The LED will have

one lead slightly longer than the other, and it is the longer lead that must

be connected to digital pin 12 and the shorter lead that should be

connected to the resistor. LEDs and some other components have the

convention of making the positive lead longer than the negative one.

To connect the resistor to the short lead of the LED, gently spread the

leads apart, and twist the short lead around one of the resistor leads, as

shown in Figure 1­17.

Figure 1­17 An LED connected to a serial resistor.

Then push the LED’s long lead into the digital pin 12 and the free lead of

the resistor into one of the two GND sockets. This is shown in Figure 1­18.

Sometimes it helps to bend a slight kink into the end of the lead so that it

fits more tightly into the socket.

Figure 1­18 An LED connected to the Arduino board.

We can now modify our sketch to use the external LED that we have just

connected. All we need to do is change the sketch so that it uses digital pin

12 instead of 13 for the LED. To do this, we change the line

to read

Now upload the sketch by clicking the Upload to IO Board button in the

same way as you did when modifying the flash rate.

BreadboardTwisting together a few wires is not practical for anything much more

than a single LED. A breadboard allows us to build complicated circuits

without the need for soldering. In fact, it is a good idea to build all circuits

on a breadboard first to get the design right and then commit the design

to solder once everything is working.

A breadboard comprises a plastic block with holes in it, with sprung metal

connections behind. Electronic components are pushed through the holes

at the front.

Underneath the breadboard holes, there are strips of connectors, so all the

holes in a strip are connected together. The strips have a gap between

them so that integrated circuits in dual­in­line packaging can be inserted

without leads on the same row being shorted together.

We can build this project on a breadboard rather than with twisted wires.

Figure 1­19 shows a photograph of this. Figure 1­20 makes it a little easier

to see how the components are positioned and connected together.

Figure 1­19 Project 1 on breadboard.

Figure 1­20 Project 1 breadboard layout.

You will notice that at the edges of the breadboard (top and bottom) there

are two long horizontal strips. The connections on the back of these long

strips run at right angles to the normal strips of connections and are used

to provide power to the components on the breadboard. Normally, there

is one for ground (0V or GND) and one for the positive supply voltage

(usually 5V).

In addition to a breadboard, you will need some jumper wires (see the

Appendix). These are short leads of a few inches in length of different

colors. They are used to make connections between the Arduino and the

breadboard. Alternatively, you can use solid­core wire and some wire

strippers or pliers to cut and remove the insulation from the ends of the

wire. It is a good idea to have at least three different colors: red for all

wires connected to the positive side of the supply, black for negative, and

some other color (orange or yellow) for other connections. This makes it

much easier to understand the layout of the circuit. You can also buy

prepared short lengths of solid­core wire in a variety of colors. Note that it

is not advisable to use multicore wire because it will tend to bunch up

when you try to push it into the breadboard holes.

We can straighten out the wires of our LED and resistor and plug them

into a breadboard. The breadboard used is often referred to as a half­size

breadboard and has 30 rows of strips, each strip being five holes, then a

gap, then another five holes. We will be using this breadboard a lot in this

book, so if you can find something as similar as possible, it will make life

easier. The actual board used was supplied by AdaFruit (see the

Appendix), but it is a very common size and layout.

SummaryWe have created our first project, albeit a very simple one. In Chapter 2

we will get a bit more background on the Arduino before moving on to

some more interesting projects.

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